This invention relates to compositions for paint and coating removal. More particularly, this invention relates to compositions containing hydrogen peroxide, water, and an organic carbonate, such as propylene carbonate, and optionally an activator and an alcohol.
Paint removing compositions are commonly used in industry, such as for stripping paint from airplane fuselages. Conventional paint remover compositions include methylene chloride, phenol, or caustic. Each of these materials, however, has inherent problems during use. While methylene chloride based compositions are very effective as paint removers, methylene chloride is a highly volatile material which is considered toxic. Similarly, phenol is highly toxic. Furthermore, caustic causes bums and attacks aluminum. Due to the deficiencies and disadvantages of conventional paint removing compositions, new paint removing compositions are highly desirable.
The present invention provides a solution to one or more of the disadvantages and deficiencies described above.
In one broad respect, this invention is a composition useful as a paint remover, comprising: an organic carbonate, hydrogen peroxide, and water. This composition, in another broad respect, is composition useful as a paint remover, comprising: an organic carbonate, an alcohol, an activator, hydrogen peroxide, and water. Representative examples of such activators include vegetable oils, naphthene, and alkyl soyate, which can improve the performance of the composition in some paint stripping applications. A representative example of an alcohol that may be used in this composition is benzyl alcohol (C6H5CH2OH). In another broad respect, this invention is a process for manufacture of a paint remover, comprising: combining effective amounts an organic carbonate, an activator, an alcohol, hydrogen peroxide, and water to form a miscible composition.
In another broad respect, this invention is a process for removing paint, comprising: applying a composition containing an organic carbonate, hydrogen peroxide, and water to a painted surface for a time and under conditions effective to cause blistering or bubbling of the paint. In another broad respect, this invention is a process for removing paint, comprising: applying a composition a painted surface for a time and under conditions effective to cause blistering or bubbling of the paint, wherein the composition comprises effective amounts of an organic carbonate, an activator, an alcohol, hydrogen peroxide, and water.
In another broad respect, this invention is a composition useful as a paint remover, comprising: effective amounts of an organic carbonate, a thickener, hydrogen peroxide, and water. This composition may also include an activator and an alcohol. This composition may optionally contain a thickener such as a polyvinyl pyrrolidone thickener. Likewise, the composition may include a compatibilizer such as a glycol ether. As used herein, the phrase xe2x80x9ceffective amountxe2x80x9d means an amount of a given component, or combination of given components, that is component effective to provide a composition capable of removing at least a portion of the paint from a painted surface. A variety of amounts will be effective in the practice of this invention. Routine experimentation by testing compositions as paint removers is all that is needed to determine effective amounts.
In another broad respect, this invention is a process for removing paint, comprising: applying a composition containing effective amounts of (a) an organic carbonate, (b) a thickener, (c) hydrogen peroxide and (d) water to a painted surface for a time and under conditions effective to cause blistering or bubbling of the paint. This composition may also include an activator and an alcohol.
The surfaces to be treated may be sealed with a variety of sealants, such as polysulfide, polyurethane, lacquer, epoxy, and the like. The compositions can be used to remove paints and coatings from furniture, automobiles, boats, trains, airplanes, military vehicles, and so forth.
This invention has a number of advantages. For example, the compositions have several important attributes, including low toxicity, high efficacy in removing paint and coatings, and neutral pH (or slightly acidic or slightly basic pH). Furthermore, in the case of propylene carbonate, the propylene carbonate breaks down into propylene glycol, which is non-toxic. Likewise, hydrogen peroxide decomposes over time to water. Hence, the propylene carbonate compositions of this invention are environmentally friendly, particularly as compared to chlorinated hydrocarbons and the like which are commonly used for paint and coating removing. In addition, the compositions of this invention cause blistering and bubbling in such a short period of time that it is envisioned that the compositions of this invention might be applied in liquid form, as opposed to the gels which are commonly applied which lesson evaporation of the chlorinated hydrocarbons, for example. Moreover, the PVP thickened compositions of this invention are peroxide stable, retain their viscosity over time, and provide clean, miscible, solutions free of phase separation, cloudiness, or flocculation. It was surprisingly found that the PVP thickeners provided superior results compared to many other types of thickeners. In particular, the PVP-thickened compositions were unique in providing clear, stable compositions. Other thickeners such as the polyacrylic acid types formed xe2x80x9cclumpsxe2x80x9d and would not disperse in the formulations. Still others, such as the Klucel(copyright) type, have now been found to thicken initially but then decrease in viscosity sharply with time on standing.
It has further been advantageously found that by employing hydrogen peroxide in the form of an at least 50% aqueous solution, a miscible solution forms with alkylene carbonate. In the context of this invention, by miscible solution it is meant a single phase solution. The resulting composition has surprisingly superior paint removing properties, which is believed to be due to the limited amount of water present. The compositions may be blended with additional cosolvents, activators, corrosion inhibitors, and the like, or may be used directly to effect paint removal. The compositions of this invention may advantageously be non-flammable, of low volatility and free of carcinogenic chemicals.